Connector and connector set

ABSTRACT

A connector and a connector set that can be fabricated by using a mold including a smaller number of components.

CROSS REFERENCE TO RELATED APPLICATIONS

This application claims benefit of priority to Japanese PatentApplication 2015-017438 filed Jan. 30, 2015, and to International PatentApplication No. PCT/JP2015/079658 filed Oct. 21, 2015, the entirecontent of which is incorporated herein by reference.

TECHNICAL FIELD

The present disclosure relates to a connector and a connector set. Moreparticularly, the present invention relates a connector and a connectorset that optically couple an optical fiber and a light emitting elementor a light receiving element to each other.

BACKGROUND

As a disclosure relating to a related-art connector, for example, anoptical module described in Japanese Unexamined Patent ApplicationPublication No. 2013-137465 is known. This optical module includes aconnector component, a lens array component, a reflective film, lightreceiving/emitting element, and a circuit board. The lightreceiving/emitting element is mounted on the circuit board. The lensarray component is attached onto the circuit board so as to cover thelight receiving/emitting element. A projection projecting rightward isprovided on a right surface of the lens array component. The connectorcomponent is provided at a distal end of an optical fiber and engagedwith the projection so as to be attached to the lens array component.That is, the projection is a positioning member that is used to positionthe connector component and the lens array component. The reflectivefilm is provided in the lens array component so as to optically couplethe optical fiber and the light receiving/emitting element to eachother. Furthermore, a lens is provided on a surface of the lens arraycomponent facing the light receiving/emitting element.

At least three components of a mold are required to fabricate the lensarray component of the optical module described in Japanese UnexaminedPatent Application Publication No. 2013-137465. In more detail, asillustrated in, for example, FIG. 6 of Japanese Unexamined PatentApplication Publication No. 2013-137465, the positioning portion is acylindrical member projecting from the right surface of the lens arraycomponent. Furthermore, the lens is provided on a lower surface of thelens array component. Accordingly, in order to form the lower surfaceincluding the lens, a first component of the mold on the lower side isrequired. Furthermore, in order to form an upper surface, a secondcomponent of the mold on the upper side is required. Furthermore, thepositioning portion is a projection projecting from the right surface.Thus, when the positioning portion is formed by using the firstcomponent or the second component of the mold, the positioning portioncannot be removed from the first component or the second component ofthe mold. Accordingly, in order to form the positioning portion, a thirdcomponent of the mold on the right side is required. As described above,for the optical module described in Japanese Unexamined PatentApplication Publication No. 2013-137465, many components of the mold arerequired. This leads to a problem in that the fabrication costincreases.

SUMMARY Technical Problem

Accordingly, an object of the present disclosure is to provide aconnector and a connector set that can be fabricated by using a moldincluding a smaller number of components.

Solution to Problem

According to a first embodiment of the present disclosure, a connectorset includes a first connector and a second connector that are to becoupled to each other. The first connector includes a first positioningsurface that is, when the first connector and the second connector arecoupled to each other, parallel to a first direction extending in adirection directed from the first connector toward the second connectorand that is, when the first connector and the second connector arecoupled to each other, parallel to a second direction perpendicular tothe first direction. The first connector also includes a secondpositioning surface spaced from the first positioning surface by adistance that is in a third direction perpendicular to the firstdirection and the second direction and that reduces from the firstconnector side toward the second connector side in the first direction.The second connector includes a first positioning portion in contactwith the first positioning surface when the first connector and thesecond connector are coupled to each other and a second positioningportion in contact with the second positioning surface when the firstconnector and the second connector are coupled to each other. None ofnormal vectors of a first surface of the second connector that faces oneside in the second direction have a component directed toward anotherside opposite to the one side in the second direction. None of normalvectors of a second surface of the second connector that faces the otherside in the second direction have a component directed toward the oneside in the second direction. None of normal vectors of a third surfaceof the second connector that faces the first connector side in the firstdirection have a component in the second direction, or none of thenormal vectors of the third surface have a component directed toward theone side in the second direction. The third surface of the secondconnector includes the first positioning portion and the secondpositioning portion.

According to a second embodiment of the present disclosure, a connectorset includes a first connector and a second connector that are to becoupled to each other. The second connector includes a third positioningsurface that is, when the first connector and the second connector arecoupled to each other, parallel to a first direction extending in adirection directed from the first connector toward the second connectorand that is, when the first connector and the second connector arecoupled to each other, parallel to a second direction perpendicular tothe first direction. The second connector also includes a fourthpositioning surface spaced from the third positioning surface by adistance that is in a third direction perpendicular to the firstdirection and the second direction and that reduces from the secondconnector side toward the first connector side in the first direction.The first connector includes a third positioning portion in contact withthe third positioning surface when the first connector and the secondconnector are coupled to each other and a fourth positioning portion incontact with the fourth positioning surface when the first connector andthe second connector are coupled to each other. None of normal vectorsof a first surface of the second connector that faces one side in thesecond direction have a component on another side opposite to the oneside in the second direction. None of normal vectors of a second surfaceof the second connector that faces the other side in the seconddirection have a component on the one side in the second direction. Inthe second connector, none of normal vectors of a third surface thatfaces the first connector side in the first direction have a componentin the second direction, or none of the normal vectors of the thirdsurface have a component directed toward the one side in the seconddirection, and the third surface includes the third positioning surfaceand the fourth positioning surface.

According to the first embodiment of the present disclosure, a secondconnector to which a first connector is to be coupled includes a firstpositioning portion, when the first connector and the second connectorare coupled to each other. A first positioning surface of the firstconnector that is parallel to a first direction extends in a directionfrom the first connector toward the second connector and is parallel toa second direction perpendicular to the first direction. The secondconnector also includes a second positioning portion, when the firstconnector and the second connector are coupled to each other. The secondpositioning surface of the first connector is spaced from the firstpositioning surface by a distance which is in a third directionperpendicular to the first direction and the second direction and whichreduces in the first direction. None of normal vectors of a firstsurface that is positioned on one side in the second direction have acomponent directed toward another side opposite to the one side in thesecond direction. None of normal vectors of a second surface that facesthe other side in the second direction have a component directed towardthe one side in the second direction. None of normal vectors of a thirdsurface that faces the first connector side in the first direction havea component in the second direction, or none of the normal vectors ofthe third surface have a component directed toward the one side in thesecond direction. The third surface includes the first positioningportion and the second positioning portion.

According to the second embodiment of the present disclosure, a secondconnector to which a first connector is to be coupled includes a thirdpositioning surface that is, when the first connector and the secondconnector are coupled to each other, parallel to a first directionextending in a direction directed from the first connector toward thesecond connector, that is, when the first connector and the secondconnector are coupled to each other, parallel to a second directionperpendicular to the first direction, and that is, when the firstconnector and the second connector are coupled to each other, contactedby a third positioning portion of the first connector. The secondconnector also includes a fourth positioning surface that is spaced froma first positioning surface by a distance which is in a third directionperpendicular to the first direction and the second direction and whichreduces from the first connector side toward the second connector sidein the first direction and that is contacted by a fourth positioningportion of the first connector. None of normal vectors of a firstsurface that faces one side in the second direction have a componentdirected toward another side opposite to the one side in the seconddirection. None of normal vectors of a second surface that faces theother side in the second direction have a component directed toward theone side in the second direction. None of normal vectors of a thirdsurface that is positioned on the first connector side in the firstdirection have a component in the second direction, or none of thenormal vectors of the third surface have a component directed toward theone side in the second direction. The third surface includes the thirdpositioning surface and the fourth positioning surface.

Advantageous Effects of Disclosure

According to the present disclosure, the connector can be fabricated byusing the mold including a smaller number of the components.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1A illustrates a plan view of an optical transmission module 10seen from above.

FIG. 1B is a sectional structural view taken along line 1-1 illustratedin FIG. 1A.

FIG. 2 is an exploded perspective view of the optical transmissionmodule 10.

FIG. 3A is a perspective view of the appearance of a receptacle 22.

FIG. 3B is a perspective view of the appearance of the receptacle 22.

FIG. 4A is a perspective view of the appearance of a metal cap 20.

FIG. 4B is a bottom view of the metal cap 20.

FIG. 5 is a perspective view of the appearance of a plug 16.

FIG. 6A is a front view of the plug 16 orthogonally projected from thefront direction.

FIG. 6B illustrates the plug 16 orthogonally projected from the reardirection.

FIG. 7 is a sectional structural view of the receptacle 22 duringfabrication.

FIG. 8A is a perspective view of the appearance of a receptacle 22 a.

FIG. 8B is a perspective view of the appearance of the receptacle 22 a.

FIG. 9A is a perspective view of the appearance of a receptacle 22 b.

FIG. 9B is a perspective view of the appearance of the receptacle 22 b.

FIG. 10 is a structural view of an optical transmission module 10′.

DETAILED DESCRIPTION A Structure of an Optical Transmission Module

A structure of an optical transmission module according to an embodimentwill be described below with reference to the drawings. FIG. 1A is aplan view of an optical transmission module 10 seen from above. FIG. 1Bis a sectional structural view taken along line 1-1 illustrated in FIG.1A. FIG. 2 is an exploded perspective view of the optical transmissionmodule 10. Hereafter, the direction of a normal to a main surface of acircuit board 12 of the optical transmission module 10 is defined as avertical direction serving as a second direction. Furthermore, in theoptical transmission module 10, a direction extending in a direction inwhich a first connector that is a plug 16 is coupled to a secondconnector that is a receptacle 22 is defined as a front-rear directionserving as a first direction. A direction from the plug 16 toward thereceptacle 22 is defined as a front direction. The vertical directionand the front-rear direction are perpendicular to each other.Furthermore, a direction perpendicular to the vertical direction and thefront-rear direction is a lateral direction serving as a thirddirection. The receptacle 22 and the plug 16 of the optical transmissionmodule 10 are arranged in the first direction. It should be understoodthat the definitions of the direction are exemplary.

As illustrated in FIGS. 1A, 1B, and 2, the optical transmission module10 is provided with the circuit board 12, the plug 16 (connector), anoptical fiber 18, a metal cap 20, the receptacle 22 (connector), a lightreceiving element array (photo-electric converter) 24, and a drivecircuit 26. Hereafter, the plug 16 and the receptacle 22 are included ina connector set 11.

The circuit board 12 is a plate-shaped member formed of BT(bismaleimide-triazine) resin, ceramic, or the like. As illustrated inFIG. 1A, the circuit board 12 has a rectangular shape in plan view whenseen from above. Hereafter, a main surface positioned on the upper sideof the circuit board 12 is referred to as a top surface, and a mainsurface positioned on the lower side of the circuit board 12 is referredto as a bottom surface. Surface mount electrodes (not illustrated) areprovided on the bottom surface of the circuit board 12. The surfacemount electrodes are to be electrically coupled to lands of a motherboard when the optical transmission module 10 is mounted on the motherboard.

Ground electrodes 80 and 82 are respectively provided near a right rearcorner and near a left rear corner of the top surface of the circuitboard 12. The potentials of the ground electrodes 80 and 82 aremaintained at a ground potential.

The light receiving element array 24 is mounted on the circuit board 12near the center of the top surface of the circuit board 12. The lightreceiving element array 24 includes a plurality of (four according tothe present embodiment) photodiodes that convert optical signals intoelectrical signals. The four photodiodes are arranged in a row along astraight line extending in the lateral direction.

The drive circuit 26 is mounted on the top surface of the circuit board12. According to the present embodiment, the drive circuit 26 isdisposed in front of the light receiving element array 24. The drivecircuit 26 includes a semiconductor circuit element that drives thelight receiving element array 24. The drive circuit 26 and the circuitboard 12 are coupled to each other through wiring lines and wiresdisposed on or in the circuit board 12. The wires are formed of Au.

Next, the receptacle 22 is described with reference to the drawings.FIGS. 3A and 3B are perspective views of the appearance of thereceptacle 22.

As illustrated in FIGS. 3A and 3B, the receptacle 22 having a box shapeis formed of transparent resin member. The material of the receptacle 22is, for example, an epoxy-based resin having light transparency. Thereceptacle 22 includes an upper surface S21 serving as a first surface,a lower surface S22 serving as a second surface, a rear surface S23serving as a third surface, a front surface S24 serving as a fourthsurface, a left surface S25 serving as a fifth surface, and a rightsurface S26 serving as a sixth surface. The upper surface S21 (firstsurface) is a top surface of the receptacle 22 that faces upward in thevertical direction. The lower surface S22 (second surface) faces thecircuit board 12 when the receptacle 22 is attached onto the circuitboard 12.

The receptacle 22 includes positioning surfaces S11 and S13, a lightinput/output surface S15, a total reflection surface 39, and a lensarray 41. The positioning surfaces S11 and S13 are formed in the rearsurface 23 by a cut that penetrates through in the vertical directionand has a projecting shape projecting from the rear direction toward thefront direction of the rear surface S23 in plan view.

The positioning surface S11 of the receptacle 22 includes a slidingsurface and a restraining surface. The sliding surface allows the plug16 to slide parallel to a direction in which optical signals transmittedbetween the plug and the receptacle 22 travel. The restraining surfacerestrains relative displacement of the plug 16 and the receptacle 22 ina direction perpendicular to the optical signal traveling direction. Forexample, a flat surface that is parallel to the front-rear direction andthe vertical direction. The normal vector of the positioning surface S11is directed in the left direction that is directed from the insidetoward the outside of the receptacle 22 and perpendicular to a surface.The distance between the positioning surface S13 and the positioningsurface S11 reduces toward the front direction. The normal vector of thepositioning surface S13 is directed toward the rear left direction. Thelight input/output surface S15 is a flat surface disposed between thepositioning surface S11 and the positioning surface S13 in the lateraldirection. The light input/output surface S15 is positioned in front ofthe positioning surfaces S11 and S13. The normal vector of the lightinput/output surface S15 is directed rearward. The positioning surfacesS11 and S13 are directly connected to both the upper surface S21 and thelower surface S22. Thus, when seen from above, the cut having atrapezoidal shape is provided at a rear edge of the receptacle 22 inplan view.

Furthermore, all the normal vectors of parts of the rear surface S23other than the positioning surfaces S11 and S13 are directed rearward.Accordingly, at least, none of the normal vectors of the rear surfaceS23 have an upward component. Preferably, none of the normal vectors ofthe rear surface S23 have an upward component or a downward component,and all the normal vectors of the rear surface S23 are parallel to aflat plane that is parallel to the front-rear direction and the lateraldirection.

The total reflection surface 39 is included in the upper surface S21 andis a flat surface formed by a recessed part of the upper surface S21.The total reflection surface 39 is positioned behind the positioningsurface S13. The normal vector of the total reflection surface 39 isdirected toward the upper front direction and inclined by 45° relativeto a plane that is parallel to the front-rear direction and the lateraldirection.

Furthermore, the upper surface S21 further includes projections 47 and48 and a recess 49. The projections 47 and 48 are spaced from the totalreflection surface 39 and respectively positioned to the left and rightof the total reflection surface 39. The projections 47 and 48 each havea cylindrical shape or a frusto-conical shape that projects upward. Theprojections 47 and 48 have diameters that allow the projections 47 and48 to be respectively fitted into inner diameters of holes 66 and 68.The diameters of the frusto-conical projections 47 and 48 reduce towardthe upper side. Accordingly, none of the normal vectors of the outercircumferential surfaces of the projections 47 and 48 have a downwardcomponent.

The recess 49 is a linear groove extending in the lateral direction andpositioned in front of the total reflection surface. None of the normalvectors of the inner peripheral surface of the recess 49 have a downwardcomponent.

Furthermore, all the normal vectors of part of the upper surface S21other than the total reflection surface 39, the projections 47 and 48,and the recess 49 are directed upward. Accordingly, none of the normalvectors of the upper surface S21 have a downward component.

Furthermore, the lower surface S22 has a recess 44. The recess 44 isformed by an upward recess in part of the lower surface S22 other thanthe outer edges. However, a cut 46 is provided on a front edge of thelower surface S22. The recess 44 communicates with the outside throughthe cut 46. The normal vectors of neither inner peripheral surfaces ofthe recess 44 nor the cut 46 have an upward component.

The lens array 41 is included in the lower surface S22 and positionedright below the total reflection surface 39 in the inner peripheralsurface of the recess 44. The lens array 41 is formed by downwardlyprojecting parts of the lower surface S22 so as to have convex shapes.The lens array 41 includes laterally arranged four convex lenses. Noneof the normal vectors of the outer circumferential surfaces of the lensarray 41 have an upward component.

Furthermore, all the normal vectors of part of the lower surface S22other than the lens array 41, the recess 44, and the cut 46 are directeddownward. Accordingly, none of the normal vectors of the lower surfaceS22 have an upward component.

The front surface S24 includes two flat surfaces S24 a and S24 b. Theflat surface S24 a is a rectangular flat surface that extends in thelateral direction. All the normal vectors of the flat surface S24 a aredirected forward. Accordingly, none of the normal vectors of the flatsurface S24 a have an upward component or a downward component. Inaddition, all the normal vectors of the flat surface S24 a are parallelto a horizontal plane that is parallel to the front-rear direction andthe lateral direction. The flat surface S24 b is a rectangular flatsurface connected to a left end of the flat surface S24 a. All thenormal vectors of the flat surface S24 b are directed toward the frontleft direction. Accordingly, none of the normal vectors of the flatsurface S24 b have an upward component or a downward component. Inaddition, all the normal vectors of the flat surface S24 b are parallelto a horizontal plane that is parallel to the front-rear direction andthe lateral direction. Thus, none of the normal vectors of the frontsurface S24 have an upward component or a downward component. Inaddition, all the normal vectors of the front surface S24 are parallelto a flat plane that is parallel to the front-rear direction and thelateral direction.

The left surface S25 is a rectangular flat surface that extends in thefront-rear direction. All the normal vectors of the left surface S25 aredirected leftward. Accordingly, none of the normal vectors of the leftsurface S25 have an upward component or a downward component. Inaddition, all the normal vectors of the left surface S25 are parallel toa plane that is parallel to the front-rear direction and the lateraldirection.

The right surface S26 is a rectangular flat surface that extends in thefront-rear direction. All the normal vectors of the right surface S26are directed rightward. Accordingly, none of the normal vectors of theright surface S26 have an upward component or a downward component. Inaddition, all the normal vectors of the right surface S26 are parallelto a horizontal plane that is parallel to the front-rear direction andthe lateral direction.

Furthermore, as will be described later, the receptacle 22 is a resinmember formed by using an upper half T1 of a mold and a lower half T2 ofthe mold to be mated with a first half T1 of the mold in the verticaldirection. In order to mate both the halves of the mold to each other,the upper half T1 is subjected to a pressure applied downward fromabove, and the lower half T2 is subjected to a pressure applied upwardfrom below. Thus, the upper half T1 and the lower half T2 of the moldare mated with each other. Accordingly, a parting line PL is formed inthe receptacle 22 by a boundary where the two halves are mated. Theparting line PL is a boundary where, when the receptacle 22 is formed bytransferring to the resin the shape of an inner space formed by mating aplurality of components of the mold to one another, the plurality ofcomponents of the mold are mated with one another. Projecting burrs andsteps may be formed in the boundary due to misalignment of matingsurfaces. As illustrated in FIG. 3A, the parting line PL is provided ata boundary between the upper surface S21 and the rear surface S23, thefront surface S24, the left surface S25, and the right surface S26. Outof a plurality of parting line regions formed by surrounding anddividing the surface of the receptacle 22 with the parting line PL, thepositioning surfaces S11 and S13 and the lens array 41 are providedwithin a single parting line region. Specifically, the positioningsurfaces S11 and S13 and the lens array 41 are positioned below theparting line PL. The shapes of the positioning surfaces S11 and S13 andthe lens array 41 are formed by transferring the shape of the lower halfT2 of the mold.

The receptacle 22 as described above is, as illustrated in FIGS. 1B and2, to be attached onto the top surface of the circuit board 12 where thelight receiving element array 24 is mounted. In more detail, thereceptacle 22 is to be attached onto the circuit board 12 with theadhesive so that the light receiving element array 24 and the drivecircuit 26 are disposed within a space formed by the inner peripheralsurface of the recess 44 and the top surface of the circuit board 12. Inso doing, the receptacle 22 is positioned so that focal points of thelenses of the lens array 41 are positioned on light receiving surfacesof the photodiodes of the light receiving element array 24.

Next, the metal cap 20 is described with reference to the drawings.FIGS. 4A and 4B are bottom views of the metal cap 20.

The metal cap 20 is fabricated by bending a single metal sheet (forexample, SUS301). The metal cap 20 includes an upper surface 50, a lowersurface 51, a left surface 52, a right surface 54, engaging portions 56and 58, holding surfaces 59, 60, and 62, and connecting portions 64 and65. The upper surface 50 has a rectangular shape. The left surface 52has a rectangular shape and is bent downward from a left edge of theupper surface 50. The right surface 54 has a rectangular shape and isbent downward from a right edge of the upper surface 50. Thus, the uppersurface 50, the left surface 52, and the right surface 54 orthogonallyprojected from the front direction form a square-cornered U shape thatis open at the bottom.

Furthermore, the upper surface 50 has an engaging piece 63 and the holes66 and 68. The engaging piece 63 is a metal piece formed by forming aU-shaped slit in the upper surface 50. The engaging piece 63 is slightlybent downward from the upper surface 50.

The hole 66 has an elliptical shape and is provided to the left frontrelative to the engaging piece 63. A longitudinal direction in which aparallel portion of the hole 66 extends is parallel to the lateraldirection. The hole 68 has a circular shape provided to the right frontrelative to the engaging piece 63.

The engaging portion 56 extends rearward from a rear end of the leftsurface 52, and then, is bent toward the right front direction.Furthermore, an end portion of the engaging portion 56 in the rightfront direction is bent leftward.

The engaging portion 58 extends rearward from a rear end of the rightsurface 54, and then, is bent toward the left front direction.Furthermore, an end portion of the engaging portion 58 in the left frontdirection is bent rightward.

The holding surface 59 projects rearward from a rear edge of the uppersurface 50 and has a rectangular shape. The holding surface 60 is bentdownward from a left edge of the holding surface 59. The holding surface62 is bent downward from a right edge of the holding surface 59. Thus,the holding surfaces 59, 60, and 62 form, in plan view seen from thefront direction, a square-cornered U shape that is open at the bottom.However, the distance between the holding surface 60 and the holdingsurface 62 is smaller than the distance between the left surface 52 andthe right surface 54.

The connecting portion 64 is connected to a rear edge of the holdingsurface 60 and extends toward the left rear direction. The connectingportion 65 is connected to a rear edge of the holding surface 62 andextends toward the right rear direction.

The metal cap 20 having the structure as described above is attachedonto the top surface of the circuit board 12 so as to cover thereceptacle 22. Specifically, the projections and 48 are respectivelyinserted into the holes 66 and 68. Thus, the upper surface 50 is broughtinto contact with the upper surface S21, the left surface 52 is broughtinto contact with the left surface S25, and the right surface 54 isbrought into contact with the right surface S26. Furthermore, thepositioning surface S11 and the positioning surface S13 are positionedbetween the holding surface 60 and the holding surface 62 in plan viewseen from the rear direction.

Lower ends of the left surface 52 and the right surface 54 are securedto the top surface of the circuit board 12 with solder, an adhesive, orthe like. Furthermore, the connecting portions 64 and 65 arerespectively secured to the ground electrodes 80 and 82 by being joinedto solder, an adhesive, or the like.

Next, the plug 16 and the optical fiber 18 are described with referenceto the drawings. FIG. 5 is a perspective view of the appearance of theplug 16. FIG. 6A illustrates the plug 16 orthogonally projected from thefront direction. FIG. 6B illustrates the plug 16 orthogonally projectedfrom the rear direction.

As illustrated in FIGS. 5, 6A, and 6B, the plug 16 having a box shape isformed of transparent resin member. The plug 16 may be formed of, forexample, polyetherimide resin or cycloolefin polymer resin.

The plug 16 includes positioning surfaces S1 and S3, a lightinput/output surface S5, and a lens array 38. The positioning surface S1is a flat surface parallel to the front-rear direction and the verticaldirection. The positioning surface S1 occupies a region near a front endof a right surface of the plug 16. The normal vector of the positioningsurface S1 is directed rightward. Furthermore, the positioning surfaceS1 is substantially parallel to the positioning surface S11 when theplug 16 and the receptacle 22 are coupled to each other. The distancebetween the positioning surface S3 and the positioning surface S1reduces toward the front direction. The positioning surface S3 occupiesa region near a front end of a left surface of the plug 16. The normalvector of the positioning surface S3 is directed toward the front leftdirection. Furthermore, the positioning surface S3 is substantiallyparallel to the positioning surface S13 when the plug 16 and thereceptacle 22 are coupled to each other. The light input/output surfaceS5 is a flat surface disposed between the positioning surface S1 and thepositioning surface S3 in the lateral direction. The light input/outputsurface S5 is positioned in front of the positioning surfaces S1 and S3.The light input/output surface S5 is a front surface of the plug 16. Thenormal vector of the light input/output surface S5 is directed rearward.Furthermore, the light input/output surface S5 is substantially parallelto the light input/output surface S15 when the plug 16 and thereceptacle 22 are coupled to each other.

The lens array 38 is provided on the front surface of the plug 16. Thelens array 38 is formed by projecting parts of the front surface of theplug 16 so as to have convex shapes. The lens array 38 includeslaterally arranged four convex lenses.

A recess 40 is provided in the left surface of the plug 16. A recess 42is provided in the right surface of the plug 16.

Furthermore, recesses 32 and 34 are provided in an upper surface of theplug 16. The recess 34 is provided near a front edge of the uppersurface of the plug 16 and has a rectangular shape in plan view whenseen from above. The recess is positioned behind the recess 34 and has arectangular shape in plan view when seen from above. Furthermore, therecess 34 extends to a rear surface of the plug 16. Accordingly, thereis a cut in part of the rear surface of the plug 16.

Furthermore, the plug 16 has a plurality of (four according to thepresent embodiment) holes 36 that allow the recess 32 and the recess 34to communicate with each other. The four holes 36 orthogonally projectedfrom the rear direction are each superposed on a corresponding one ofthe four lenses of the lens array 38.

The optical fiber 18 includes four core wires and jackets that cover thefour core wires. The core wires include cores and claddings formed ofresin such as fluorine based resin. Furthermore, the jackets are formedof resin such as polyethylene based resin. As illustrated in FIG. 1B,the jackets are removed from part of the optical fiber 18 near a distalend of the optical fiber 18, so that the core wires are exposed.Hereafter, portions where the core wires are exposed are referred to asexposed portions 18 b. Furthermore, portions where the core wires arecovered with the jackets are referred to as covered portions 18 a.

The four exposed portions 18 b are each inserted into a correspondingone of the four holes 36 from the rear direction. The distal ends of thefour exposed portions 18 b are positioned right behind the four lensesof the lens array 38 in the recess 34, respectively. At this time, theoptical axes of optical signals traveling from distal end surfaces ofthe four exposed portions 18 b (core wires) are parallel to thefront-rear direction.

Furthermore, resin having transparency is poured into the recesses 32and 34. In more detail, the recesses 32 and 35 are physically opticallycoupled to the optical fiber 18 through transparent acrylic resin or thelike. Thus, the optical fiber 18 is secured to the plug 16. That is, theplug 16 is provided at the distal end of the optical fiber 18.

The plug 16 structured as described above is coupled to the receptacle22. Specifically, the plug 16 is inserted from the rear direction into aspace surrounded by the holding surfaces 59, 60, and 62 and the circuitboard 12. When the plug 16 is moved forward, the positioning surface S3of the plug 16 is brought into contact with the positioning surface S13of the receptacle 22. The plug 16 moved further forward in this state isdisplaced rightward along the positioning surface S13. Then, when thepositioning surface S1 of the plug 16 is brought into contact with thepositioning surface S11 of the receptacle 22, the rightward displacementof the plug 16 is restrained. The forward and rightward movement of theplug 16 is stopped. This determines the positions of the plug 16 and thereceptacle 22 relative to each other in the lateral direction. Thepositioning surfaces S1 and S11 serve as reference surfaces for therelative positions of the plug 16 and the receptacle 22 in the lateraldirection. Then, the engaging portions 56 and 58 of the metal cap 20 arerespectively brought into engagement with the recesses 40 and 42 of theplug 16, and the connecting portion 64 of the metal cap 20 is broughtinto engagement with the recess disposed in an intermediate portion ofthe plug 16 in the front-rear direction. Thus, the plug 16 is secured tothe receptacle 22.

Here, when the plug 16 and the receptacle 22 are coupled to each other,the distal ends of the four core wires of the optical fiber 18 arrangedin the lateral direction to form a flat shape extending parallel to thevertical direction and the lateral direction are respectively opticallycoupled to the light receiving surfaces of the four photodiodes of thelight receiving element array 24 arranged in the lateral direction onthe top surface of the circuit board 12. Specifically, a plurality ofoptical signals radiated from the distal ends of the four core wires ofthe optical fiber 18 travel forward and are incident upon the lens array38. The lens array 38 collimates the optical signals which are in theform of laser beams, so that the optical signals become more similar toparallel light. After that, the optical signals enter the plug 16through the light input/output surface S15.

The total reflection surface 39 that changes the traveling direction ofthe optical signals and extends in the lateral direction is provided infront of the light input/output surface S15 with a certain distancetherebetween. Specifically, the optical signals having traveled forwardare reflected by the total reflection surface 39 so as to be redirecteddownward, thereby being incident upon the lens array 41. The lens array41 concentrates the laser beams that form the respective optical signalsonto the light receiving element array 24. As a result, the lightreceiving element array 24 receives the optical signals and generateselectrical signals. As has been described, when the plug 16 and thereceptacle 22 are coupled to each other, the total reflection surface 39performs the function of optically coupling the distal ends of the corewires of the optical fiber 18 and the light receiving element array 24to one another. Furthermore, when the plug 16 and the receptacle 22 arecoupled to each other, the lens array 41 is provided between the totalreflection surface 39 and the light receiving element array 24 andperforms the function of concentrating the laser beams onto the lightreceiving surfaces of the light receiving element array 24. Here, alight emitting element array may be used instead of the light receivingelement array 24. In this case, optical signals radiated from aplurality of light emitting element arrays of the board pass through thelens array 41 and are incident upon the optical fiber 18.

About a Method of Fabricating the Receptacle 22

Next, a method of fabricating the receptacle 22 is described withreference to the drawings. FIG. 7 is a sectional structural view of thereceptacle 22 during fabrication of the receptacle. FIG. 7 illustratesthe sectional structure of the receptacle 22 taken along line 1-1illustrated in FIG. 1.

As illustrated in FIG. 7, the receptacle 22 is formed by injecting resininto a space formed by two halves of the mold, that is, the upper halfT1 serving as a first half of the mold and the lower half T2 serving asa second half of the mold. Specifically, the upper half T1 is used toform a portion of the receptacle 22 on the upper side relative to theparting line PL (that is, the upper surface S21). The lower half T2 isused to form a portion of the receptacle 22 on the lower side relativeto the parting line PL (that is, the lower surface S22, the rear surfaceS23, the left surface S25, and the right surface S26).

While the upper half T1 is subjected to a pressure applied downward fromabove and the lower half T2 is subjected to a pressure applied upwardfrom below, the resin is supplied into an inner space of the mold formedby the upper half T1 and the lower half T2. As a result, the shape ofthe upper surface

S21 including the total reflection surface 39 is formed by transferringthe shape of the upper half T1. The shape of the lower surface S22including the lens array 41, the rear surface S23 including thepositioning surfaces S11 and S13, and the flowability of the resinsupplied into the mold can be controlled through temperature change orchemical change. The shapes of the left surface S25 and the rightsurface S26 are formed by transferring the shape of the lower half T2.By performing the above-described steps, the receptacle 22 is completed.It is noted that a flowability of the resin supplied into the innerspace of the mold can be controlled through temperature change orchemical change. In order to fabricate the resin members, a fabricationmethod such as injection molding, transfer forming, or compressionmolding can be used.

Next, the receptacle 22 is attached onto the circuit board 12.Specifically, a photo-curing adhesive, a UV curing adhesive in moredetail, is applied to the top surface of the circuit board 12. Next, thereceptacle 22 is attached onto the top surface of the circuit board 12so as to cover the light receiving element array 24 and the drivecircuit 26. After that, ultra-violet light is radiated to cure theadhesive.

Next, the metal cap 20 is attached onto the top surface of the circuitboard 12 so as to cover the receptacle 22. Specifically, a thermosettingadhesive such as epoxy based resin is applied to the top surface of thecircuit board 12. Furthermore, conductive paste such as Ag is applied tothe ground electrodes 80 and 82 of the circuit board 12. Next, the metalcap 20 is attached onto the top surface of the circuit board 12. Afterthat, heat is applied to the circuit board 12 by using an oven to curethe adhesive and the conductive paste. Thus, the metal cap 20 is securedto the circuit board 12.

The plug 16 is fabricated by injection molding using a mold similarly tothe receptacle 22. However, since a method of fabricating the plug 16 isgenerally known, description of the method is omitted.

Effects

According to the receptacle 22 of the present embodiment, the receptacle22 can be fabricated by using a mold including a smaller number ofcomponents. In more detail, none of the normal vectors of the uppersurface S21 have a downward component, and none of the normal vectors ofthe lower surface S22 have an upward component. Accordingly, the uppersurface S21 can be formed by using the upper half T1, and the lowersurface S22 can be formed by using the lower half T2.

Here, the rear surface S23 of the receptacle 22 including thepositioning surfaces S11 and S13 is a flat surface that does not have adeformed portion in the lateral direction perpendicular to a matingdirection of the upper and lower halves of the mold when separating fromthe parting line PL. Or, the rear surface S23 of the receptacle 22 isnormally tapered, that is, inclined inward toward the directionseparating from the parting line PL in the lateral direction.Preferably, none of the normal vectors of the rear surface S23 have anupward component or a downward component. That is, in the case where therear surface S23 is formed by using the lower half T2, when thereceptacle 22 is removed from the lower half T2, the rear surface S23has no irregularities or a reverse taper that is caught by the lowerhalf T2. Thus, for the connector set 11, a separate component of themold other than the upper half T1 and the lower half T2 is not requiredto form the rear surface S23 of the receptacle 22. As a result, thereceptacle 22 can be fabricated by using a mold including a smallernumber of components.

Furthermore, in the receptacle 22, none of the normal vectors of thefront surface S24 have an upward component or a downward component, noneof the normal vectors of the left surface S25 have an upward componentor a downward component, and none of the normal vectors of the rightsurface S26 have an upward component or a downward component. Thus, inthe case where the front surface S24, the left surface S25, and theright surface S26 are formed by using the lower half T2, when thereceptacle 22 is removed from the lower half T2, none of the frontsurface S24, the left surface S25, or the right surface S26 hasirregularities that are caught by the lower half T2. Thus, for theconnector set 11, a separate component of the mold other than the halfT1 and the half T2 of the mold is not required to form the front surfaceS24, the left surface S25, and the right surface S26 and the receptacle22. As a result, the receptacle 22 can be fabricated only with the twohalves of the mold, that is, the upper half T1 and the upper half T2.

Furthermore, with the receptacle 22, the occurrence of fabricationvariation of positional relationships between the positioning surfacesS11 and S13 and the lens array 41 can be suppressed. In more detail, thepositioning surfaces S11 and S13 and the lens array 41 are positionedbelow the parting line PL. That is, the shapes of the positioningsurfaces S11 and S13 and the lens array 41 are formed by transferringthe shape of the same lower half T2. Accordingly, even when there ismisalignment in position between the upper half T1 and the lower halfT2, no misalignment occurs in the positional relationships between thepositioning surfaces S11 and S13 and the lens array 41. Accordingly, thedistal ends of the core wires of the optical fiber 18 and the lightreceiving element array 24 can be optically coupled to each other withgood accuracy.

The total reflection surface 39 is formed by using the upper half T1.Accordingly, there may be the occurrence of fabrication variation of thepositional relationships between the total reflection surface 39 and thepositioning surfaces S11 and S13 and between the total reflectionsurface 39 and the lens array 41. However, such fabrication variationdoes not significantly adversely affect the optical coupling between thedistal ends of the core wires of the optical fiber 18 and the lightreceiving element array 24. In more detail, the total reflection surface39 has, in plan view seen from above, a flat surface that uniformlyextends in a direction perpendicular to the signal traveling directionand has a large size sufficient to surround the light receiving elementarray 24. The total reflection surface 39 has, when orthogonallyprojected from the front side, a flat surface that uniformly extends ina direction perpendicular to the signal traveling direction and has alarge size sufficient to surround the distal ends of the core wires ofthe optical fiber 18. Accordingly, even when the position of the totalreflection surface 39 is deviated in the front-rear direction or thelateral direction, the optical coupling between the distal ends of thecore wires of the optical fiber 18 and the light receiving element array24 is maintained as long as the above-described surroundingrelationships are not lost.

Furthermore, with the receptacle 22, the occurrence of fabricationvariation of the positional relationships between the positioningsurfaces S11 and S13 and the lens array 41 can be suppressed also forthe following reason. In more detail, the positioning surfaces S11 andS13 are directly connected to the lower surface S22. Thus, thepositioning surfaces S11 and S13 and the lower surface S22 can be formedby using the lower half T2. That is, the shapes of the positioningsurfaces S11 and S13 and the lower surface S22 can be formed bytransferring the shape of the same lower half T2. Accordingly, theoccurrence of fabrication variation of the positional relationshipsbetween the positioning surfaces S11 and S13 and the lens array 41 canbe suppressed.

Furthermore, with the receptacle 22, the plug 16 and the receptacle 22can be positioned with good accuracy. In more detail, the positioningsurface S1 is substantially parallel to the positioning surface S11 whenthe plug 16 and the receptacle are coupled to each other. Thepositioning surface S2 is substantially parallel to the positioningsurface S13 when the plug 16 and the receptacle 22 are coupled to eachother. Accordingly, the positioning surface S1 and the positioningsurface S11 are brought into surface contact with each other, and thepositioning surface S2 and the positioning surface S13 are brought intosurface contact with each other. Thus, when the plug 16 and thereceptacle 22 are coupled to each other, the occurrence of play betweenthe plug 16 and the receptacle 22 is suppressed. Accordingly, with thereceptacle 22, the plug 16 and the receptacle 22 can be positioned withgood accuracy.

Furthermore, with the receptacle 22, removal of the receptacle 22 fromthe circuit board 12 is suppressed. In more detail, in order to attachthe receptacle 22 onto the top surface of the circuit board 12, theadhesive is supplied between the lower surface S22 of the receptacle 22and the circuit board 12 and heated to be cured. In so doing, air in thespace surrounded by the inner peripheral surface of the recess 44 of thereceptacle 22 and the top surface of the circuit board 12 is heated andexpands. Accordingly, the pressure in the space increases. Thus, a forceto remove the receptacle 22 from the circuit board 12 is applied.Accordingly, the cut 46 that is a through hole allowing communicationbetween the recess 44 and the outside is provided in the receptacle 22.Due to the presence of this cut 46, the increase in pressure in thespace is suppressed. As a result, removal of the receptacle 22 from thecircuit board 12 is suppressed.

Furthermore, with the receptacle 22, breakage of Au wires coupling thedrive circuit 26 and circuit board 12 to each other during thermal shocktesting is suppressed. In more detail, in an optical transmission moduleusing a typical receptacle, a circuit board and a drive circuit arecoupled to each other through Au wires. Furthermore, the drive circuitis covered and sealed with, for example, epoxy based resin havingtransparency. Since the circuit board, the Au wires, the epoxy basedresin, and the drive circuit are made of different materials, theseelements have different coefficients of linear expansion. For thisreason, in an optical transmission module using a related-artreceptacle, the Au wires may break due to a load applied to the Au wiresduring thermal shock testing.

In contrast, in the optical transmission module 10, the drive circuit 26is not sealed with resin. Specifically, the Au wires are disposed in aspace formed by a recess of the receptacle 22. Accordingly, in theoptical transmission module 10, compared to a typical opticaltransmission module in which the Au wires are sealed with resin, athermal stress load applied during thermal shock testing to the Au wires(not illustrated) coupling the drive circuit 26 and the circuit board toeach other is small. As a result, in the optical transmission module 10,breakage of the Au wires coupling the drive circuit 26 and the circuitboard 12 to each other during thermal shock testing is suppressed.

Furthermore, with the optical transmission module 10, the structure ofthe receptacle 22 can be simplified. In more detail, in the opticaltransmission module 10, a guide surface for the plug 16 is formed by theholding surfaces 59, 60, and 62 of the metal cap 20. Accordingly, it isnot required that the receptacle 22 be provided with a rail that guidesinsertion/removal movements of the plug 16. As a result, the structureof the receptacle 22 is simplified.

Furthermore, in the optical transmission module 10, easy removal of theplug 16 from the receptacle 22 is suppressed. In more detail, in theoptical transmission module 10, the engaging portions 56 and 58 arerespectively engaged with the recesses 40 and 42. During coupling of theplug 16 and the receptacle 22 to each other, a right end and a left endof the engaging portions 56 and 58 are respectively pressed by a leftsurface and a right surface of the plug 16, thereby the engagingportions 56 and 58 are elastically deformed into warped shapes. Then,when the right end and the left end of the engaging portions 56 and 58respectively reach the recesses 40 and 42, the states of the engagingportions 56 and 58 return back to the original states, and the engagingportions 56 and 58 are brought into engagement with the recesses 40 and42.

Here, since the engaging portions 56 and 58 are comparatively long, theengaging portions 56 and 58 can be largely elastically deformed. Forthis reason, even when the amount of rightward projection of theengaging portion 56 and the amount of leftward projection of theengaging portion 58 are increased, the engaging portions 56 and 58 canbe sufficiently elastically deformed into warped shapes during couplingof the plug 16 and the receptacle 22 to each other. Thus, the depth ofthe recesses 40 and 42 of the plug 16 can be increased. Accordingly, theengaging portions 56 and 58 can be more firmly engaged with the recesses40 and 42. As a result, easy removal of the plug 16 from the receptacle22 is suppressed.

Furthermore, in the optical transmission module 10, plastic deformationof the metal cap 20 is suppressed. In more detail, the connectingportions 64 and 65 are respectively connected to the rear edges of theholding surfaces 60 and 62 and secured to the ground electrodes 80 and82 of the circuit board 12. Accordingly, when the plug 16 and thereceptacle 22 are coupled to each other, excessively large deformationof the holding surfaces 60 and 62 due to contact with the plug 16 issuppressed by the connecting portions 64 and 65. As a result, plasticdeformation of the metal cap 20 is suppressed.

Furthermore, in the optical transmission module 10, removal of the metalcap 20 from the circuit board 12 is suppressed. In more detail, theengaging piece 63 is in pressure contact with the surface on the upperside of the plug 16. When the plug 16 is secured to the receptacle 22only with such an engaging piece 63, it is required that the engagingpiece 63 be in pressure contact with the plug 16 with a large force. Inthis case, however, a large force is applied between the circuit board12 and the metal cap 20. This may lead to removal of the metal cap 20from the circuit board 12.

Accordingly, in the optical transmission module 10, the plug 16 isinterposed between the engaging portions 56 and 58 on the left and rightsides so as to be held in the receptacle 22. This holding with theengaging portions 56 and 58 does not apply a large force between thecircuit board 12 and the metal cap 20. As a result, removal of the metalcap 20 from the circuit board 12 is suppressed.

Furthermore, the metal cap 20 having lower ends that are kept alignedcan be easily mounted on the circuit board 12 in the opticaltransmission module 10.

A Receptacle According to a First Variant

Hereafter, a receptacle 22 a according to a first variant is describedwith reference to the drawings. FIGS. 8A and 8B are perspective views ofthe appearance of the receptacle 22 a.

The structures of the positioning surfaces S11 and S13 and the lightinput/output surface S15 of the receptacle 22 a are different from thoseof the receptacle 22. The following description of the receptacle 22 ais mainly made for these differences.

The positioning surfaces S11 and S13 and the light input/output surfaceS15 of the receptacle 22 are in contact with the lower surface S22. Thatis, the positioning surfaces S11 and S13, the light input/output surfaceS15, and the lower surface S22 connect the upper surface S21 and thelower surface S22 to each other.

In contrast, the positioning surfaces S11 and S13 and the lightinput/output surface S15 of the receptacle 22 a are not in contact withthe lower surface S22. Thus, a gap is formed between the top surface ofthe circuit board 12 and the positioning surfaces S11, the positioningsurface S13, and the light input/output surface S15 when the receptacle22 a is attached onto the top surface of the circuit board 12. As aresult, during mounting of the receptacle 22 a on the circuit board 12,solder is contained in the gap between the top surface of the circuitboard 12 and the positioning surface S11, the positioning surface S13,and the light input/output surface S15. This suppresses adhering of thesolder to the positioning surfaces S11 and S13 and the lightinput/output surface S15. As a result, misalignment in positioning ofthe receptacle 22 a and the plug 16 due to the solder is suppressed.

A Receptacle According to a Second Variant

Hereafter, a receptacle 22 b according to a second variant is describedwith reference to the drawings. FIGS. 9A and 9B are perspective views ofthe appearance of the receptacle 22 b.

The structure of the light input/output surface S15 of the receptacle 22b is different from that of the receptacle 22 a. The followingdescription of the receptacle 22 b is mainly made for this difference.

When positioning the receptacle 22 b and the plug 16 to each other,prevention of adhering of the solder to the positioning surfaces S11 andS13 is more important than adhering of the solder to the lightinput/output surface S15. Accordingly, in the receptacle 22 b, thepositioning surfaces S11 and S13 are not in contact with the lowersurface S22, and the light input/output surface S15 is in contact withthe lower surface S22. With the receptacle 22 b as described above,misalignment in positioning of the receptacle 22 b and the plug 16 dueto the solder is suppressed as is the case with the receptacle 22 a.

An Optical Transmission Module according to a Variant

Hereafter, an optical transmission module 10′ according to a variant isdescribed with reference to the drawing. FIG. 10 is a structural view ofthe optical transmission module 10′.

The structures of a plug 16′ and a receptacle 22′ of the opticaltransmission module 10′ are different from the corresponding structuresof the optical transmission module 10. In more detail, the plug 16′ hasthe structure of the receptacle 22, and the receptacle 22′ has thestructure of the plug 16. The structures of the receptacle and the plugmay be interchanged as described above.

A method of fabricating the plug 16′ is the same as the method offabricating the receptacle 22.

Other Embodiments

The optical transmission module, the receptacle, the plug, the connectorset, and the method of fabricating the receptacle according to thepresent disclosure are not limited to the optical transmission module,the receptacle, the plug, the connector set, and the method offabricating the receptacle according to the above-described embodimentsand can be changed within the scope of the gist of the presentdisclosure.

The lens array 41 and parts of the positioning surfaces S11 and S13 maybe positioned below the parting line PL. In this case, the lens array 41and the parts of the positioning surfaces S11 and S13 are formed byusing the half T2 of the mold. However, as illustrated in FIG. 3A, it ispreferable that the lens array 41, the entirety of the positioningsurface S11, and the entirety of the positioning surface S13 bepositioned below the parting line PL.

The normal vectors of each of the front surface S24, the left surfaceS25, and the right surface S26 may include both of a normal vectorhaving an upward component and a normal vector having a downwardcomponent.

Furthermore, the positioning surfaces S1, S2, S11, and S12 may be curvedsurfaces instead of flat surfaces.

Furthermore, as long as the positioning surfaces S11 and S13 aresurfaces, for example, positioning portions such as projections may beused instead of the positioning surfaces S1 and S3. Furthermore, as longas the positioning surfaces S1 and S3 are surfaces, for example,positioning portions such as projections may be used instead of thepositioning surfaces S11 and S13.

Furthermore, it is sufficient that none of the normal vectors of therear surface S23 have an upward component, or none of the normal vectorsof the rear surface S23 have a downward component.

INDUSTRIAL APPLICABILITY

As has been described, the present disclosure is useful for theconnector and the connector set. In particular, the present disclosureis excellent for fabricating the connector with a smaller number ofcomponents of the mold.

1. A connector set comprising: a first connector and a second connectorthat are to be coupled to each other, wherein the first connectorincludes a first positioning surface that is, when the first connectorand the second connector are coupled to each other, parallel to a firstdirection extending in a direction directed from the first connectortoward the second connector and that is, when the first connector andthe second connector are coupled to each other, parallel to a seconddirection perpendicular to the first direction, and a second positioningsurface spaced from the first positioning surface by a distance that isin a third direction perpendicular to the first direction and the seconddirection and that reduces from a side of the first connector toward aside of the second connector in the first direction, wherein the secondconnector includes a first positioning portion in contact with the firstpositioning surface when the first connector and the second connectorare coupled to each other, and a second positioning portion in contactwith the second positioning surface when the first connector and thesecond connector are coupled to each other, wherein none of normalvectors of a first surface of the second connector that faces one sidein the second direction have a component directed toward another sideopposite to the one side in the second direction, wherein none of normalvectors of a second surface of the second connector that faces the otherside in the second direction have a component directed toward the oneside in the second direction, wherein none of normal vectors of a thirdsurface of the second connector that faces the first connector side inthe first direction have a component in the second direction, or none ofthe normal vectors of the third surface have a component directed towardthe one side in the second direction, and wherein the third surface ofthe second connector includes the first positioning portion and thesecond positioning portion.
 2. The connector set according to claim 1,wherein the first positioning portion is a surface that is parallel tothe first positioning surface when the first connector and the secondconnector are coupled to each other, and wherein the second positioningportion is a surface that is parallel to the second positioning surfacewhen the first connector and the second connector are coupled to eachother.
 3. The connector set according to claim 1, wherein the firstconnector is a plug provided at a distal end of an optical fiber, andwherein the second connector is a receptacle.
 4. The connector setaccording to claim 3, wherein the first direction is parallel to adirection in which an optical axis extends at the distal end of theoptical fiber.
 5. The connector set according to claim 3, wherein thereceptacle is attached onto a circuit board where a photo-electricconversion element is mounted, and wherein the receptacle furtherincludes a total reflection surface that optically couples the distalend of the optical fiber and the photo-electric conversion element toeach other when the plug and the receptacle are coupled to each other.6. The connector set according to claim 5, wherein the second surface ofthe receptacle faces the circuit board, wherein, when the firstconnector and the second connector are coupled to each other, the firstpositioning portion is a surface that is parallel to the firstpositioning surface and that is not in contact with the second surface,and wherein, when the first connector and the second connector arecoupled to each other, the second positioning portion is a surface thatis parallel to the second positioning surface and that is not in contactwith the second surface.
 7. The connector set according to claim 6,wherein the receptacle further includes a lens that is provided betweenthe total reflection surface and the photo-electric conversion elementand that has a focal point positioned on the photo-electric conversionelement.
 8. The connector set according to claim 7, wherein the secondsurface includes the lens, and wherein the first positioning portion andthe second positioning portion are directly connected to the secondsurface.
 9. The connector set according to claim 8, wherein thereceptacle is a resin member formed by using a first half of a mold anda second half of the mold to be mated with the first half of the mold inthe second direction, and wherein at least part of the first positioningportion, at least part of the second positioning portion, and the lensare positioned on the other side in the second direction relative to aparting line formed at a boundary between the first half of the mold andthe second half of the mold.
 10. The connector set according to claim 9,wherein the first positioning portion, the second positioning portion,and the lens are positioned on the other side in the second directionrelative to the parting line.
 11. The connector set according to claim1, wherein the second connector is a plug provided at a distal end of anoptical fiber, and the first connector is a receptacle.
 12. Theconnector set according to claim 1, wherein none of normal vectors of afourth surface of the second connector that faces the first connectorside in the first direction have a component in the second direction, ornone of the normal vectors of the fourth surface have a component on theone side in the second direction, wherein none of normal vectors of afifth surface of the second connector that is positioned on one of sidesin the third direction have a component in the second direction, or noneof the normal vectors of the fifth surface have a component on the oneside in the second direction, and wherein none of normal vectors of asixth surface of the second connector that is positioned on another sidein the third direction have a component in the second direction, or noneof the normal vectors of the sixth surface have a component on the oneside in the second direction.
 13. A connector set comprising: a firstconnector and a second connector that are to be coupled to each other,wherein the second connector includes a first positioning surface thatis, when the first connector and the second connector are coupled toeach other, parallel to a first direction extending in a directiondirected from the first connector toward the second connector and thatis, when the first connector and the second connector are coupled toeach other, parallel to a second direction perpendicular to the firstdirection, and a second positioning surface spaced from the firstpositioning surface by a distance that is in a third directionperpendicular to the first direction and the second direction and thatreduces from the second connector side toward the first connector sidein the first direction, wherein the first connector includes a firstpositioning portion in contact with the first positioning surface whenthe first connector and the second connector are coupled to each other,and a second positioning portion in contact with the second positioningsurface when the first connector and the second connector are coupled toeach other, wherein none of normal vectors of a first surface of thesecond connector that faces one side in the second direction have acomponent on another side opposite to the one side in the seconddirection, wherein none of normal vectors of a second surface of thesecond connector that faces the other side in the second direction havea component on the one side in the second direction, wherein, in thesecond connector, none of normal vectors of a third surface that facesthe first connector side in the first direction have a component in thesecond direction, or none of the normal vectors of the third surfacehave a component directed toward the one side in the second direction,and wherein the third surface includes the first positioning surface andthe second positioning surface.
 14. A second connector to which a firstconnector is to be coupled, the second connector comprising: a firstpositioning portion in contact with, when the first connector and thesecond connector are coupled to each other, a first positioning surfaceof the first connector that is parallel to a first direction extendingin a direction directed from the first connector toward the secondconnector and that is parallel to a second direction perpendicular tothe first direction, and a second positioning portion in contact with,when the first connector and the second connector are coupled to eachother, the second positioning surface of the first connector that isspaced from the first positioning surface by a distance which is in athird direction perpendicular to the first direction and the seconddirection and which reduces in the first direction, wherein none ofnormal vectors of a first surface that is positioned on one side in thesecond direction have a component directed toward another side oppositeto the one side in the second direction, wherein none of normal vectorsof a second surface that faces the other side in the second directionhave a component directed toward the one side in the second direction,wherein none of normal vectors of a third surface that faces the firstconnector side in the first direction have a component in the seconddirection, or none of the normal vectors of the third surface have acomponent directed toward the one side in the second direction, andwherein the third surface includes the first positioning portion and thesecond positioning portion.
 15. A second connector to which a firstconnector is to be coupled, the second connector comprising: a firstpositioning surface that is, when the first connector and the secondconnector are coupled to each other, parallel to a first directionextending in a direction directed from the first connector toward thesecond connector, that is, when the first connector and the secondconnector are coupled to each other, parallel to a second directionperpendicular to the first direction, and that is, when the firstconnector and the second connector are coupled to each other, contactedby a first positioning portion of the first connector, a secondpositioning surface that is spaced from the first positioning surface bya distance which is in a third direction perpendicular to the firstdirection and the second direction and which reduces from the firstconnector side toward the second connector side in the first directionand that is contacted by a second positioning portion of the firstconnector, wherein none of normal vectors of a first surface that facesone side in the second direction have a component directed towardanother side opposite to the one side in the second direction, whereinnone of normal vectors of a second surface that faces the other side inthe second direction have a component directed toward the one side inthe second direction, wherein none of normal vectors of a third surfacethat is positioned on the first connector side in the first directionhave a component in the second direction, or none of the normal vectorsof the third surface have a component directed toward the one side inthe second direction, and wherein the first surface includes the firstpositioning surface and the second positioning surface.